Initial Reset; Initial Reset Factors; Reset Pin - Epson S1C17001 Technical Manual

5 Initial Reset

5.1 Initial Reset Factors

Shown below are the three different initial reset factors for initializing S1C17001 internal circuits.
(1) External initial reset via #RESET pin
(2) External initial reset via P0 port (pins P00 to P03) key entry (set by software)
(3) Internal initial reset via watchdog timer (set by software)
Figure 5.1.1 illustrates the initial reset circuit configuration.
#RESET
P00
Chattering filter
P01
circuit
P02
P03
The CPU and peripheral circuits are initialized by initial reset factors. The CPU begins reset processing once the
factors are canceled.
This causes the reset vector to be read from the start of the vector table, and the program (initialization routine)
starting at that address to be executed.

5.1.1 #RESET pin

Initial resetting is possible by inputting external Low level to the #RESET pin.
To initialize the S1C17001 reliably, the #RESET pin must be maintained at Low level for at least the specified du-
ration after the power supply voltage rises. (Refer to "24.5 AC Characteristics.")
Initial resetting is canceled if the #RESET input changes from Low to High, and the CPU begins reset interrupt
processing.
The #RESET pin incorporates a pull-up resistance.
S1C17001 TECHNICAL MANUAL
Key reset
control circuit
P0KRST
Watchdog timer
WDTMD
Figure 5.1.1: Initial reset circuit configuration
EPSON
Oscillation stabilization
standby circuit
Digital noise
filter
5 INITIAL RESET
Internal
S Q
reset
R
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